JPH022045A - Method and device for direct color printing - Google Patents

Abstract

PURPOSE: To enhance the reliability by one-dimensionally moving a print medium to the two-dimensional array of an exposure generating element and deciding the effects of the exposure generating element on the print medium in response to an input signal which represents an image by a controller. CONSTITUTION: A carrier 100 carrying a microcapsule passes over a platen 41 from a position on a paper feed reel 40, then passes through a clearance between pressure rollers 42, 43 and finally is taken up by a take-up reel 44. When the carrier 100 passes on the platen 41, the microcapsule is carried facing the opposite side to the platen 41. An image is generated when the carrier 100 passes under a modulator 45, being exposed to three different colors. The carrier 100 thus exposed is matched to a color print paper at the pressure rollers 42, 43 and the microcapsule is ruptured by the pressure of the pressure rollers 42, 43. Further, a chemical substance liberated by the rupture is absorbed by the matched paper, then the paper passes through a heater and through this process, a coloring matter is formed to fix an image.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to color and monochrome electronic image processing, and more particularly to the production of color and monochrome prints of images represented by multiplex signals.

color cathode ray tube
tube, CRT) is the most popular Nice Play technology.

They are used in a variety of applications from home video displays to high-resolution computer-aided design. Currently, most analog video images have intermediate spatial resolution (typically 521 horizontal by 480 vertical pixels or less). However, higher resolution displays are becoming available, especially in commercial environments. CR
T is also characterized by a generally continuous intensity, hue and saturation.

In order to take full advantage of the advantages of video, C-spray technology, a compatible printing technology is required to transfer video images onto hardcopy media, such as color prints. Areas that can benefit from color pictures include routine business notes, catalog sales, real estate advertising, sales terminals, videotex applications, law enforcement, electronic photography, and home entertainment.

Color hard copy printers currently on the market employ a variety of technologies. Ink jet printing technology involves spraying rapidly drying ink droplets (yellow, crimson, blue, and/or black) onto paper. The main disadvantages of inkjet printing are that the hardware is complex, costly, and easily clogged. be.

Furthermore, thermal transfer uses two techniques: direct transfer and indirect transfer. In monochrome direct thermal transfer printing, the printhead heats the chemical-containing paper to a “brush point,”
Here, the two chemicals in the paper combine to create an image. In indirect transfer, wax-ink is applied to the printhead or to the polymer substrate.
The ink is transferred onto the paper by liquefying or sublimating it. A simple thermal transfer printer can easily print in only eight colors. Heat sublimation printers have the ability to provide continuous tones. The main disadvantages of thermal transfer printing are speed and difficulty in matching the three basic colors. Electrostatic color printing is similar to the familiar black and white printing first introduced by Xerox. This differs only in that each of the three basic colors needs to be treated independently by separate exposures, toner fixatives, etc. The main disadvantages of electrostatic color printing technology are the complexity, high cost, and stringent alignment requirements associated with the optical system and hardware associated with it to "unfold" the print. It is. High quality color printing can be achieved with color photography by using a CRT and color separation filters. Traditional film processing techniques are very slow, and while instant photography is convenient, it suffers from high printing costs, short film shelf life, and poor cohesiveness of disposable elements.

Two recent advances in photosensitive recording materials have made it possible to produce video printers with image quality approaching that of standard photographic printers, but with lower printing costs and less processing complexity. . Mead Corporation
(Dayton, Ohio) is a microencapsulation
) and photopolymerization (phoLopolymeri
Photosensitive “paper” (PAP) based on zaLion technology
The fully colorimetric version of this paper has the ability to produce color continuous tone images when exposed to visible light from 400 to 700 nm. Regarding this microencapsulation technique. is 1
August 16, 983 - Sander
U.S. Patent No. 4,399.20 issued to S. et al.
9, and Electronic Image''/'j (E
electronic imaging), 198
4, a paper published on pages 35-41 [Photocapsule process for hard copy output (Photoca
psuleProcess for Hardcopy
)]. This 'photosensitive' paper, which has a sensitivity approximately 1/1000 times that of standard photographic film, transfers exposed microcapsule sheets to a receiving sheet (
receiver3hcet) and rupture the microcapsules with a pressure roller. This pressure releases the dye precursor, which produces an image on the receiver color print sheet by chemical reaction with the acid of the receiver. When the color print sheet is heated to a temperature of about 100° C., the formation of dye occurs within a few seconds by chemical reaction with the acid on the receiver sheet. . This is a dry process and the only disposable material is the microcapsule sheet. This system is expected to reduce the cost per print because it uses only organic dyes and does not use silver.

3M Company (St. Paul, Minn.) has successfully developed a colored version of the dry silver vapor that has been used for many years within the monochrome CRT video printing system. wavelength and has approximately 100 times less sensitivity than standard instant color film.It is processed by heating the exposed vapor to a temperature of approximately 132°C for approximately 10 seconds and contains no disposable elements. .

The key to success for these newly developed photosensitive recording materials, as well as for more established recording materials, is their ability to produce the high light levels required by spatial resolution and the color gamut required by color CRT displays. It is a compact and fast printer. This printer is required to have low basic costs, low operating costs, and be mechanically reliable. None of the known approaches can meet all of these requirements.

These requirements are met by projection mode or near contact mode printing systems that employ large area patterns of exposure producing elements, such as controllable light sources. wherein the pattern of exposure generating elements is a row (
column).

All of the light sources within an individual row contribute to the exposure of individual pixels within a corresponding row of the resulting color print, as appropriate. This large area pattern of light sources can be achieved by a variety of approaches ranging from using multiple light sources to a single light source with appropriate light modulators or CRTs. In one approach, liquid crystal light modulators are used for the three basic colors.

The main disadvantage of printers using CRT n-optical systems is that the exposure source and optical modulator are the same device. This greatly limits the available intensity and spectral range of the emitted light. In addition, CRTs are often not raster-geometrically stable and are subject to variations due to beam intensity and position, component aging, etc.

Exposure efficiency of CRT-based printers is also an issue. In other words, a conventional camera projects the entire received image onto the film at once, resulting in all pixels (
pexel) are stored in parallel, whereas a CRT distributes pixels serially. In printer systems with 512 lines and 480 pixels/line (approximately 1/4 of a million pixels), differences in operating modes result in large differences in exposure efficiency! I can do it. Of course, this does not take into account processing time, but the fact remains that CRT-based systems are slow. This is especially true for CRTs.
The system must handle camera optics,
This becomes noticeable when the level of light from the CRT is low. Measured comparisons clearly show that it is advantageous to use as much parallelism as possible and therefore a parallel array of controllable light sources rather than a CRT source. However, the controllable light source approach also has problems. First, optical reduction of the image
In the absence of n), these light sources must be very close to the light source. That is, if a 5 x 5 inch print must display 500 x 500 pixels, the light sources should not be more than 0.01 inch apart. High resolution requires small distances and color processing requires very careful matching in processing the three basic colors. Second, in using an array of light sources, it is important to obtain equal light intensities from the individual light sources in response to similar stimuli. This requires correction of damaged or out-of-spec devices.

In accordance with the principles of the present invention, it is an object and problem to provide a method for employing an array of exposure producing elements, e.g., controllable illuminators, inksheet elements, etc., with a suitable print medium and moving the same relative to each other. This is achieved by the printer used. In the context of the present disclosure, the exposure generating element is a plurality of illumination devices, where one illumination device is one element that provides controllable light at its output port. Of course, the important thing is that it is the illumination function that exposes the print media.
n). In print media of the type described above, this illumination function is accomplished by multiple light transmitting elements. This light may exit the element, or it may exit from outside the element, causing the element to function as a light modulator.

Thus, in the context of this disclosure, an exposure generation array has rows and columns of illuminators. photosensitive print media
The print medium) is moved relative to the array parallel to the rows of the array, while the illuminator is digitally turned on and off to provide exposure light. The light generating array includes three segments of illumination devices, each segment providing one of three basic colors. Individual elements within a row expose individual pixels within the row of exposed media to achieve the required intensity. As a result, printers constructed according to principles according to the present invention have various advantages that other printers do not have. For example, since multiple columns are used, the print media traverses every individual column, where the potential contribution of each individual column is the same, and if one column is damaged, this This can be easily overcome by disabling the damaged column and using another column in its place. Because a large area is available for exposing the print media, high intensity light does not have to be used, reducing the negative effects that high intensity light has on the light modulator. While the data is digital, the resulting image is largely analog. Although processing with digital signals is usually simpler than with analogues, the principles employed by the printer of the present invention can be applied just as easily in the context of analogue signals.

Figures 1 and 2 show an example to explain the above principle. In FIG. 1, a sheet of print media 10 is shown having a square area 20 consisting of 16 pixels (4×4) shown thereon. Pixels along the diagonal (up and to the right) are not exposed, and the remaining pixels are exposed to different degrees. More specifically, within region 20 there are a single diagonally shaded pixel, e.g. pixel 21, which indicates a level 1 exposure; a double diagonally shaded pixel, which indicates a level 2 exposure. ,
For example, 5 pixels 22; and level 3 where double diagonal lines cross
There is a pixel, for example, pixel 23, which shows an exposure of . Level 2 exposure can be achieved with twice the amount of light, ie by exposing twice as long. A similar approach is taken for all levels of exposure.

In the following discussion describing FIG. 2 in more detail, the square area 20 of FIG. 1 is represented by an array of the following numbers corresponding to the exposure intensities:

As mentioned above, the print media is exposed by moving it relative to an array of light sources. This relative movement is parallel to the rows in the array of light sources. In FIG. 2, this is illustrated by eight views of print media 10 and light source device 30. In FIG. The device 30 is
It has four rows and three columns 30. The exposure of a pixel is controlled by the number of light sources providing light to that pixel in a row of devices 30 across the pixel. Pixels on the print medium 10 are exposed at maximum level 3 exposure, so
For example, since one pixel is exposed three times, the number of required light sources in each row of device 30 is three, and therefore the second
Do not exceed the number of columns shown in the diagram. As will be apparent from the following description, according to the principles of the present invention, the array of light sources requires several "rows" in the direction of relative movement of the print medium to the array of light sources; “
Note that "columns" are not required; however, an array of rows and columns as shown in FIG. 2 simplifies the management of some electronic signals.

The operations illustrated in FIG. 2 relate the array of numbers given above to exposure positions on the print media, and also associate this number with the columns within the array of light sources when the print media reaches those columns. They can be best understood by relating them. The latter association can be seen as a set of registers associated with individual columns of the optical array,
The columns of the number array are loaded from the left. Here, the number in the register in the left column is moved to the register in the right column as the print medium moves to the right.

According to the invention, the individual registers add different threshold values to the numbers in these registers. By this method, by selecting an appropriate threshold, each individual pixel is illuminated the correct number of times as it passes under the array. One approach to achieve this different threshold is to decrement the numbers as they are moved from one set of column registers to another and use 0 as the threshold. . If the number in a register is greater than 0, the corresponding light source supplies light to the pixel below it;
If not, do not supply. Of course, other approaches are also possible. For example, threshold values added to a column do not necessarily have to be in order.

If you pay attention to the stiffness, you can easily analyze Figure 2. In FIG. 2(1), the print medium is not under the light source 30. In FIG. Therefore, neither of these numbers is associated with any columns within device 30.

In FIG. 2(2), the first column of pixels of medium 10F is below the left-most column of light source 30, and following the approach described above, the left-most column of device 30 has a number Columns in an array! Information regarding the following is provided:

Based on these numbers, the lower three light sources in the leftmost column of device 30 (unless their values are greater than 0) expose the pixels below them. In FIG. 3, the first and second columns of media 10 are each below the left-most column of device 30, and according to the approach described above, the left-most column of device 30 has a number information about column 2 in the array is provided, while the middle column is provided with the number previously associated with the leftmost column of device 30, but decremented by 1 (0 is decremented). (not divided). Therefore, the number stored in this column register is as follows.

Based on these numbers, the top one and bottom two light sources in the left-most column of the device will be able to match their bottom pixels to the middle two light sources in the center column of the device 30. Exposure with light.

In FIG. 2(4) all three columns of the device 30 are above the medium 10. The control numbers associated with these columns are as follows.

Then, according to these numbers, the appropriate light source in the device 30 exposes the pixels below them.

Exposures (5) through (8) are performed and the final pattern is provided as the print medium exits the right side of the device 30.

Some prints introducing the principles of the invention'b
The aspect can be easily configured. - As an example, FIG.
In FIG. 3, a carrier carrying stiff microcapsules in the form of a paper roll is placed at position 7 on paper feed reel 40. It will be done. From reel 40, vapor (100) passes over platen 41, then between pressure rollers 42 and 43, and finally to a take-up reel.
l) taken by 44. The passage of the carrier carrying the microcapsules on the platen 41 is carried out in such a way that the microcapsules are facing away from the platen.

Above the platen 41 and the microcapsule carrier there is a light modulator 45 , and above the modulator 45 there are three light sources 46 including two fluorescent lamps 47 and one light reflector 48 . Between the individual reflectors 48 and the open end of the modulator 45 a filter is provided for color separation, which could also be a narrow band phosphor. Filter 51 passes only the spectral portion of the light that activates only the yellow color within the microcapsules, filter 52 passes only the spectral portion of the light that activates only the blue color within the microcapsules, and filter 53 passes only the spectral portion of the light that activates only the blue color within the microcapsules. Only the part of the spectrum of light that activates the deep red color within the capsule is passed through.

The printer of FIG. 3 also includes a supply reel 49 which stores color printing paper onto which the image is transferred once the microcapsules have been properly exposed. For this purpose, color printing paper is passed between pressure rollers 42 and 43 so that it overlaps with the microcapsules of the carrier. Following the pressure roller system, the color print paper exits the printer after passing through a heater 50.

In operation, an image is created when the carrier carrying the microcapsules is passed under the modulator 45 and exposed to three colors. The exposed carrier is aligned with the color printing paper at the pressure rollers 42 and 43, and the microcapsules are released by the pressure of the rollers [tl!
torn apart. The released chemicals (dye precursors) are absorbed by the aligned paper and the vapor then passes through a heater where dye formation occurs and the image is fixed.

Modulator 45 performs the function of FIG. Although device 30 has been described as a "light source," it can be seen from FIG. 3 that the invention is not limited to active light emitting means, such as LEDs or controllable laser beams. In the embodiment of FIG. 3, the printer uses a single light source and light modulator or bulb for each color, which together constitute the "light source." Modulator 45 can be constructed in a variety of ways, but the most convenient approach is to use a conventional active-matrix-addressed twisted nematic liquid crystal array (active-matrix-addressed twisted nematic liquid crystal array).
ressed twisted-nemat, ic
1iquid crystallary). In fact, a liquid crystal (LC) with 480 rows and containing 440 addressable cells per row is commercially available from Seiko-Epson.

The design flexibility allowed by another light valve is illustrated in FIG. 4 with a geometry chosen as one of the compromises between accuracy and cost. Figure 4 shows a tB pure rectangular design. This includes a row's address line 54 and a column's address line 55 located perpendicular to the row's address line.
including. Appropriate levels exist at each intersection of row and column address lines. individual transistors 56
is connected to the associated liquid crystal display pixel 60, which emits light when the transistor is activated.

One interlayer in the design of FIG. 4 is the separation between elements 60, which allows insertion of row address lines 54 and causes black (unexposed) lines to appear in the color print. This artifact
is clearly undesirable.

FIG. 5 avoids this problem by dividing the pixels 60 into two groups and shifting one group relative to the other so that the pixels on one group are aligned with the address lines of the other group. This shows a somewhat complex design. This shift also doubles the linear resolution in the column direction.

When pixels along a column are given numbers (to address), one group takes odd numbers and the pixels in the other group take even numbers.

Although the configuration of FIG. 5 provides complete coverage along the column direction, the boundaries between one pixel and the next are too sharp, which also causes undesirable artifacts. In the design of FIG. 6, the shape of the pixels 60 is trapezoidal and the size is such that the trapezoids in one group overlap the trapezoids in the other group. This solves the problem of transitions between odd and even pixels.

FIG. 7 shows the modulator configuration in a more macroscopic manner, showing odd and even groups and three color groups for a total of six groups. In this implementation, there are 31 column segments (allowing a dynamic range defined by 5 bits) and 2 columns per column.
40 cells are adopted. The clear cell area of pixel 60 is 0.009 inches (square) on each side, and the center-to-center distance is 0.
．． It is 0188 inches.

Although FIG. 7 shows individual color group exclusion, it is of course possible to achieve similar results using a different configuration. For example, the columns in Figure 7 could be arranged in sets of three, with each set containing one column for each of the three colors. Columns within each set are arranged in different orders and pixel interleaving
You can also do this. Such different configurations, of course, require correspondingly different signal driving devices.

The considerations discussed above in connection with FIGS. 4-6 pertain to only one of the two orthogonal directions that make up the final color print. That is, it only concerns the direction perpendicular to the relative movement of the print media.

With respect to the direction along the relative movement of the print medium, important considerations include not only the shape and position of the pixel 60;
Since these two are related in terms of hardness, the property of relative movement is also included. The first consideration is one that does not affect the characteristics of the print; should the print medium be moved relative to the printer body and the modulator should be fixed, or should the light modulator be moved and the print medium be fixed? The question is whether it should be done. Although the printer of FIG. 3 moves the print media, there are several advantages (eg, size, complexity, etc.) that suggest the use of this approach. Another problem is one that affects color prints, where movement is ill
The question is whether it should be moved continuously or in steps. Continuous movement is simpler to implement, lower cost, and the device is generally more reliable, while step movement allows more free control of single pixel definitions. This is because in the case of continuous movement, blurring of pixel boundaries inevitably occurs in the direction of movement. From the simple discussion above of artifacts, some blurring is desirable, so the question is simply whether the blurring due to continuous movement is tolerable. Continuous movement is preferred if this is acceptable, or if it can be controlled to an acceptable extent by adjusting the speed of movement relative to the switching time of the light modulator.

Another important consideration is the delivery of light by the modulator. This consideration depends on the degree of delivery at the wavelength required by the print media, the "turn-on" by the pixel 60,
turr + on)” and “turn off (turn o
ff)", how uniform and equal the light provided by the filters (51, 52, and 53 are), how collimated the light applied to the modulator 45 (
collimate); and the distance between the modulator 45 and the exposed print medium. All of these considerations are well known to those skilled in the art, and a variety of well-known design choices can be made to achieve the desired results. In Figure 3, for example, each of the three color devices is
It has one fluorescent lamp source 47 and one reflector 48. The modulator is placed very close to the print media to avoid light scattering.

A two-dimensional collimator array is used in combination with the LC array to collimate the light emerging from the light source 47 and reflector 48. FIG. 8 shows a configuration with two layers of collimators. In FIG. 8, two thick aperture array ports 5, a polarizer 66, a thin transparent membrane 67, an analyzer 68, and an active matrix addressed liquid crystal modulator 45 are shown.

The aperture array forms a collimator array, which defines the acceptance angle and active pixel area for each individual pixel and eliminates crosstalk between adjacent pixels.
k) to prevent These are Corning Photo Serum (
It can be formed by chemically processing a Corning Fotocram™ plate from both sides. The etched holes have a rough surface that scatters light diffusely. For collimation to function efficiently within the near-contact printing system of FIG. 3, it is necessary that the diffused light be highly absorbed within the light valve. The reflection coefficient for Fotoceram varies from 0°25 in the red range of the light spectrum to approximately 0.05 in the blue range of the light spectrum, with off-axis multiply scattered light (off-axis multiply 5cat
terd rays) are highly attenuated.

A polarizer 6 is placed between the upper collimator array 65 and the modulator 45.
By placing a can be reduced. A thin transparent cover sheet 67 is included to prevent dust particles from entering the holes in the upper array 65. For the lower collimator array 65, an analyzer 68 provides a dust barrier function.

By the way, appropriate shading of the cover sheet 67 also helps to achieve uniform luminous intensity.

As Moe moves on to describe the electronics associated with color printing in accordance with the present invention, several issues regarding mechanical design should be mentioned.

In the context of Mead microencapsulated print media, providing a means to reverse the movement of the print media can minimize the amount of "vapor" that is discarded. The mechanism for this is not shown in FIG. 3 as it is well known in the art.

The system shown in FIG.
It is designed for Mead print media that requires 5 sheets. - For 3M Dry Silver Vapor, the pressure roller transfer sheet roll and the pick-up roll are removed and the exposed sheet is fed directly into the processing heater. The quality of 3M Dry Silver Vapor and standard photographic materials is less sensitive to temperature and humidity than Mead “vapor” and has less stringent environmental control requirements. , the effect of temperature on the shelf life of vapor.

In order to avoid rapid deterioration of vapor inside the printer, the internal temperature should be kept below 30 degrees, and for this purpose a fan is required.

Another problem, related to light uniformity, is related to the fact that the scanning speed for the three basic colors is the same. Therefore, the lamp intensities assigned to individual colors must be monitored and managed to ensure the correct exposure level. In current technology, this
This means that each lamp must have an independent light sensor and control circuit. To make full use of the available light, the lower surface of the lamp in the printer of FIG. 3 is placed very close to the sheet 67, and to avoid complications Physical shutters to limit exposure of the liquid crystal to light are eliminated. Therefore, some means is needed to turn on the lamps just before the scan begins, bring them up to a controllable level by the time the exposure begins, and turn them off after a predetermined period of the scan. Become.

The light profile across the array in the scan direction is determined by both the upper collimation, the meter-to-lamp spacing, and the reflector design. However, in practice it is very difficult to obtain a uniform light intensity profile, whereas it is relatively easy to make it symmetrical about the centers of the individual color segments. This non-uniformity can be easily corrected electronically by modifying the intensity values applied to the threshold electronics, which will be explained later.

In addition to kneading, Mead "paper" and 3M Dry Silver both tend to have a gamma of 1 or more. The nonlinearity of the light profile can also be used to achieve gamma correction in a manner that does not require a linear polarizer or sacrifice available light intensity.

Finally, in the context of the more conventional aspects of the printer according to the invention, the fluorescent lamps should be powered from an AC source to ensure a reasonable lifetime. It is also economically advantageous to drive them from a 120 volt 60 Hz AC line. The basic exposure period of pixel 60 is 60
With frequencies that are not submultiples of Hz, beat frequencies occur, which give vertical light and dark bands in the image. These can be eliminated by making the scan period an integer multiple of the power period. However, even if this measure is not taken, each individual pixel will still have up to 311S light
The cycle is exposed, so the beat amplitude is a small fraction of the lowest exposure level.

The operating speed of a printer according to the invention depends on the available light intensity, the sensitivity of the photosensitive medium, the number of pixels to be sequentially exposed, the number of lines on the scanning window which determines the effective aperture of the system, and the LC3. Related to switching time. The latter factor is most directly under the designer's control.

The modulator of FIG. 7 consists of a rectangular array with rows and columns. According to the mode of operation described above, all of the columns operate in parallel, and due to the addressing characteristics of this row/column configuration, this means that the pixels within the individual columns are processed sequentially, whereas the individual It means that pixels within a row are processed in parallel, or vice versa. In order to enhance parallelism, it is best to select a mode that allows parallel w1m of as many pixels as possible. On the other hand, the selection of either option is governed by the required product aspect ratio, the modulator 45 aspect ratio, and the manner in which the data is provided. Odd numbers explained above/
In an even pixel configuration, the two rows corresponding to one odd/even bear are actually rows of pixels that can be controlled in parallel if the individual groups of pixels (odd/even) have column control lines in the case. It is one row. Sequential processing of pixels within a column creates problems in printers that employ continuous movement of the print medium because of the skew that is created. Sequential processing of columns rather than rows easily avoids this skew problem.

FIG. 9 shows a partial diagram of the electronic circuitry required to control one color segment of modulator 45. Parts not shown are either identical to those shown or are entirely conventional. This circuit is very simple. For signals coming from sources such as televisions,
Figure 9 shows the frame grabber.
r) Provide 70. The function consists in capturing one frame of the image, and the design is entirely conventional. Control circuit 71 interacts with grabber 70 and directs grabber 70 to simultaneously output its pixel information onto the red (R), green (G), and blue (B) buses. More specifically, grabber 70 provides bare R, G, and B buses, one for even pixels and one for odd pixels. Control circuit 71 also provides a base clock signal and a word clock signal to circuit 80 (shown only once in FIG. 9), which is synchronized with the R, G, and B bus signals. Thus, picture information for one individual bus is provided to circuit 80 by grabber 70 in substantially the same manner as it was input thereto. That is, one row is scanned at - degrees and one row is provided at - degrees. The only difference is in the use of even and odd tracks of pixels. The word clock signal is also added to the counter 72 clock input, while the vertical synchronization (Vsync) signal from control 71 is used to reset counter 72. The output of counter 72 is applied to a 1 to N demodulator 73 which generates an activation signal for modulator 45 low.

Within each circuit 80, the input data signal (of one of these colors) is applied to a shift register 81 (column register in the above description). The length of this register is designed to hold information for all pixels in one picture row. here,
A column is defined as containing only odd or even pixels. The signal strength of an individual pixel is defined in a 5-bit word, but one sign bit is provided to facilitate manipulation of the decrement function between column registers, as described above. Circuit 80 includes a serial chain of registers (interconnected via a decrement circuit), but this number
equal to the number of columns in each color segment of . Thus, the output of register 81, which receives its input signal from grabber 70, is connected to a subsequent register 81 via a decrement circuit. This decrement circuit is a simple serial adder 85
along with a control port that applies a signal corresponding to carry flip-flop 86 and -1.

In operation, the value exiting one register 81 is decremented by one before being inserted into the next register 81.

The six first stages of individual registers 81 provide their contents to a test circuit 82, which produces an output of "1" only when all inputs are "0".
gate 83 using OR gate 83 and the word clock signal.
includes a flip-flop 84 that captures the state of the . The output signal of the flip-flop 84 associated with the first register 81 is applied to the first column (even or odd);
The output signal of the next flip-flop 84 in the chain is applied to the second column, and so on.

The description above FIG. 4 describes a compact embodiment in which Mead vapor is used and a fluorescent lamp is used as the light source, while FIG. 10 depicts a configuration employing a conventional incandescent light source and collimation of discs. show. Additionally - by way of example, 3M Dry Silver Vapor is used in Figure 10.

In FIG. 10, light source 82 is referred to as a "point source".
This "point source" can be realized in a conventional manner using a projection lamp, mask and associated optics to the desired intensity. The output of light source 82 is collimated by lens 83. , this lens can be a standard lens or a Fresnel lens.The collimated light output of lens 83 is applied to an LCD assembly 84. Assembly 84 is shown in FIG.
It is similar to the CD assembly in that it includes elements 66, 45 and 68, but it does not require collimator 65 and cover 67, but instead uses color separation filters (51, 52 and 53) and optical means to prevent the liquid from hitting the paper at non-active areas (masks) of the LCD array. The printer of FIG. 10 also requires a paper supply reel 40 and heater 50, but unlike the printer of FIG. 4, it does not require a transfer sheet supply roller, pressure roller, or take-up roller.

[Brief explanation of the drawing]

FIG. 1 shows an exemplary color print medium with 16 pixel areas exposed to different light intensities; FIG. 2 is a sequence diagram of how to achieve the exposure pattern of FIG. 1; FIG. Figures 4-6 illustrate one embodiment of a printer employing three fluorescent light sources incorporating the principles of the present invention: Figures 4-6 illustrate different pixel patterns that can be used within the light modulator of Figure 3: Figure 7 8 is an overall view of the address bus pattern within the light modulator of the printer of FIG. 3; FIG. 8 illustrates one approach for collimating light passing through the light modulator of the printer of FIG. 3; and FIG. 9 schematically shows some of the circuitry necessary to control the modulator of FIG. 3; and FIG. 10 shows an embodiment of the printer using a single light source. [Explanation of symbols of main parts] 0...Reel...Platen, 2.43...Rolling roller 5...Light modulator 6...Light source 7... ... Fluorescent lamp 8 ... Light reflector 0 ... Heater 1.52.53 ... Filter FIG. FIG. FIG.

Claims (1)

Claims: 1. An apparatus for applying an image onto a print medium, the apparatus comprising: a two-dimensional array of exposure-generating elements for generating an exposure-generating excitation applied onto the print medium; relative to the array and along the surface; and determining the effect of the exposure generating element on the print medium in response to an applied input signal representative of the image; An apparatus for direct color printing, characterized in that it includes a controller for direct color printing. 2. The apparatus of claim 1, wherein the exposure generating elements form a two-dimensional array, the array including rows aligned with movement of the print medium along the surface. 3. The apparatus of claim 1, wherein the exposure generating element provides zero or a predetermined non-zero amount of exposure generating energy to the print medium. 4. The apparatus of claim 1, wherein the exposure generating elements are comprised of a plurality of groups, each group providing a different effect on the media. 5. The apparatus of claim 4, wherein said individual groups develop different colors on said print media. 6. The apparatus of claim 1, wherein the exposure generating element is an illumination device. 7. The device according to claim 6, wherein the illumination device has a trapezoidal shape. 8. The device of claim 6, wherein the illumination device is a light bulb. 9. Claim 6, wherein the lighting device is a light source.
The device described. 10. The device of claim 6, wherein the illumination device is a light modulator. 11. The apparatus of claim 10, wherein the controller includes a light source for adding light to the array of lighting devices. 12. The controller further includes means for collimating the light output of the light source.
The device described. 13. The apparatus of claim 1, wherein the array comprises rows of exposure producing elements. 14. The apparatus of claim 13, wherein the means for moving the print media moves the print media parallel to the rows relative to the array. 15. The array further includes columns, some columns are connected to some rows, and some other columns are connected to some other rows. 14. The device according to claim 13, characterized in that it is connected to: ). 16. The apparatus of claim 13, wherein the controller includes means for applying input signals of different colors to different columns (rows). 17. One column (row) where the controller is further
17. Apparatus according to claim 16, characterized in that it includes means for applying a common effective threshold for varying the operating state of the exposure generating element within the column and different effective thresholds for different columns (rows). 18. The apparatus of claim 17 further comprising means for disabling selected columns (rows). 19, comprising a print medium and an array of exposure-generating elements having a row of elements, the individual exposure-generating elements being activated when the print medium is placed in a physical coupling position corresponding to the element; A method for developing a print on a print medium for use in an apparatus for creating visible contrast in the print medium, the method comprising: placing the print medium in a bonding position corresponding to the array in the row. recursively identifying the to-be-excited element of the exposure generating element in the row based on the applied input signal; A method for direct color printing, characterized in that it comprises the step of exciting appropriate elements of the exposure generating element during said moving step.